Hello, My name is Mark and I have been using Reefmaster for a few months, creating charts for my Lowrance Elite 7 HDI.

However, I have noticed that I have a problem with contour colour band whereby two successive bands have the same colour.

I have generated the chart with a custom palette that was based on earlier topic for the Elite 4 HDI and it works well except that two adjacent bands display in Reefmaster and on the Elite in the same blue colour shown in the first picture, 21ft & 24ft levels are the same blue.

I discovered the RGB palettes display different colours for those bands but not AT5. The custom palette has different colour shades for all the selections, see picture 2.

I have found a work around, where I create a copy chart and then edit the ISOBATHs manually. I saw that before I edited the ISOBATHS the two adjacent ISOBATHS were the same colour number. So, by setting the ISOBATH manually in the copied map for all those at that level, the maps displays correctly in Reefmaster and on the Elite. see picture 3.

I wonder if this is something I have incorrectly setup or a possible bug?

Any advice would be greatly appreciated.

thanks, Mark

Hi Mark,

This is expected behaviour with AT5 palettes.
There are a fixed number of colours (12) in an RM palette which must be distributed across the depth levels in a map. If there are more than 12 depth areas, then some bands will have the same colour.
The reason this happens with AT5 palettes (and not RGB) is that we cannot interpolate between AT5 colours - each AT5 colour has a distinct id number that is used in the unit to identify that colour. Hence every colour band in the map is an exact match to an AT5 colour in the palette.

RGB palettes work a little differently, in that we can interpolate between the colours to produce as many shades as we need, so you should never see adjacent bands with the same colours when using an RGB palette.

Later Lowrance units (Gen2+) now support RGB palettes, and we will introduce support for that in RM in time. Earlier units are stuck with AT5 colour ids.

Workarounds include the one that you are using, as well as creating palettes with a greater number of colours. The latter method isn't directly supported in RM but there are a couple of threads on this forum that detail how to do it (and we plan to make the number of palette entries editable in the RM palette editor at some point). Another technique that can produce very nice results is to create a user map with graded transparency for depth areas. Alternatively, you can get any colours you like by using one of the raster background export options - either flat raster or shaded relief exports can be made with both AT5 and RGB palettes.

Matt

Hi Matt,
Many thanks for a prompt response & the alternative workarounds.

Mark.